Alloy comprising iron, nickel, chromium, tungsten, or molybdenum



i I I i l I PIERRE GIRIN, OFJPARIS, FRANCE, ASSIGNORTO SOCIETE ANONYMEDIE COLENTRY, FOUBCHBAULT dc JDJECAZJEVILLE, F PARIfi lFNfiE.

ALLOY COMPRISING IRON, NI, CHROMIUM, TIJ' NGSTEN, OR MOLYBDENUM.

No Drawing.

To'all whom it may concern:

Be it known that I, PIERRE Gmm, a citizen of the Republic of France,residing in Paris, France, have invented certain new n and usefulImprovements in a New Alloy Comprising Iron, Nickel, Chromium, Tungsten,or Molybdenum, of which the following is a specification.

The attainment of an industrial alloy hav- 1o ing a high mechanicalresistance at hi h temperatures and capable of indefinit y preservingits properties, in spite of a prolonged exposure ,to these temperatures,is

- a problem which has not yet received a practical solution. In fact,the most resistant reheating annuls the action of the treatment.

The hi h speed steels certainly preserve their ardnes's at a temeraturehigher than the other steels, and after they have been tempered possessa high resistance even up to a red heat, but besides the drawbacks whichresult from their fragility and dimculties of a practical'nature due tothe extremely high temperature of their-treatment, they do not presentthe desired stability W when the temperature exceeds 600; in fact,

not only an accidental excess of temperature beyond the regulated value,but even prolonged exposure to this temperature produce a gradualdisappearance of the initial hardness and a progressive diminution ofresistance. Finally, they are very oxidizable.

In addition, the invention of gas motors, gas turbines and other thermalmachines intended to act above the temperature of red heat, and thediscovery of chemical synthetic processes using at the same time hightem peratures and high pressures, render the realization of a metalpossessing certain qualities at high temperature extremely desirable.

The present invention concerns an alloy of iron, nickel, chromium andtungsten, and including, perhaps, molybdenum or vanadium, cobalt andtitanium. This alloy is easy to obtain in large quantities, and capableof being moulded, forged, rolled, wire drawn, or otherwise Worked,without dimculty, possessing at the temperature of 800 a resistancealmost equivalent to that of cold iron, non-fragile, practicallyinoxidizable at Application filed December 9, 1918. Serial No. 2%,985.

high temperatures, even in a very oxidizing temperature, and at the sametime possessing properties which are strictly reversible; by this termwe understandthat the properties at a given temperature depend solely onthat temperature and in no Way on the preceding temperatures that havebeen'obtained,

nor on an exposure. more or-less long to the temperature used. The alloymay contain,

for example:

- Per cent.

Nickel to Chromium 10 to 15 Tungsten 2 to 5 Manganese 1 to 2 Carbon 0.3to 0.6

Iron forming the remainder.

defined 0.5 to 1 per cent of vanadium, or

0.1 to 0.2 per cent of titanium.

The alloy thus obtained forms a solid homogeneous solution; no thermaltreatment can, consequently, modify its properties. The combined actionof chromium and of tungsten (this last metalbeing capable of beingreplaced wholly or partially by molybdenum) and, if it is present, ofvanadium, is to confer on the alloy of iron and nickel a very highresistance when heated; we can obtain easily 25 to 35 kgs. per sq. mm.with an elastic limit of 20 to 30 kgs. and a coefiicient of elongationof 40 per cent at. a temperature of 800, while still preserving a totalabsence of fragility. These additional elements also render the alloyextremely resistant to the attack of acid vapours, as well as of hotoxidizing and moist gases This chemical unalterability is of thegreatest. importance for all applications, since it not only ensures themetal against corrosion, but also ensures the preservation of theinitial mechanical properties, in contradistinction to thatwhich takesplace with carbon steels which, when heated for a long time in anatmosphere rich in hydrogen, finally become decarburized and lose theirsolidity.

This alloy is certainly very suitable for the manufacture of gasturbines, or for receptacles employed in chemical industry, forreactions which take place at high temperature and at high pressures,and which pro duce corrosive gases or other substances.

Having thus described the nature of the said invention and the bestmeans I know of carrying the same into practical effect, I claim Ahighnickel ferrous alloy containing 10 nickel, 60 to 70 per cent,chromium, 10 to 15 per cent, tungsten, 2 to 5 per cent, manganese l to 2per cent and carbon, 0.3 to 0.6 per cent, such alloy having at elevatedtemperatures great mechanical resistance and also great resistance tochemical agents and susceptible of retaining indefinitely its initialproperties, notwithstanding prolonged service. v

In witness whereof, I have hereunto signed my name.

PIERRE GIRIN.

